Bearing positioning structure for motor

ABSTRACT

A bearing positioning structure for a motor includes an axial tube and a positioning member. The positioning member includes a pressing portion and a coupling portion. The coupling portion of the positioning member is engaged with a coupling section of the axial tube for securely mounting the positioning member to the axial tube, with the pressing portion of the positioning member pressing against a bearing to position the bearing in the axial tube. In another example, the coupling portion of the positioning member engages with a coupling section on a stator.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a positioning structure for a motorand, more particularly, to a bearing positioning structure for a motorwith a positioning member providing with a coupling portion and apressing portion for stably positioning at least one motor component inan axial tube of a base.

2. Description of Related Art

FIG. 1 of the drawings illustrates a conventional bearing positioningstructure for a motor 1 comprising a base 11, a stator 12, a supportingmember 13, a bearing 14, a positioning member 15, and a rotor 16. Thebase 11 includes an axial tube 111 for receiving the bearing 14. Thestator 12 includes a winding 121. The supporting member 13 is fixed inan end of the axial tube 111 by force-fitting. An abrasion-resistingmember 131 is mounted in a lower end of the supporting member 13. Arestraining member 132 is placed on top of the supporting member 13 andincludes a through-hole (not labeled) for retaining a shaft 161 of therotor 16. The positioning member 15 is mounted on top of the bearing 14to prevent the bearing 14 from moving relative to the axial tube 111 ofthe base 11, thereby assuring reliable assembly.

Still referring to FIG. 1, in assembly, the supporting member 13, thebearing 14, and the positioning member 15 are mounted into the axialtube 111 of the base 11 in sequence, with the supporting member 13 andthe positioning member 15 respectively fixed in two ends of the axialtube 111 by force-fitting, thereby positioning the bearing 14 in theaxial tube 111. The shaft 161 is rotatably extended through an axialhole (not labeled) formed by a through-hole in each of the bearing 14and the positioning member 15 and a hole (not labeled) in the supportingmember 13.

Still referring to FIG. 1, when the motor 1 turns, since the diameter ofthe through-hole of the retaining member 132 on top of the supportingmember 13 is smaller than an end of the shaft 161 and since theretaining member 132 is engaged in a necked portion (not labeled) of theshaft 161, the rotor 16 is prevented from disengaging from the bearing14. Further, the bearing 14 is prevented from moving in the axial tube111, as the positioning member 15 is force-fitted in an end of the axialtube 111 of the base 11, with a bottom of the positioning member 15pressing against a top of the bearing 14. Hence, the bearing 14 and theshaft 16 are reliably coupled to the base 11.

However, the above conventional bearing positioning structure for amotor has some drawbacks. First, the axial tube 111 easily deforms aftera period of time due to heat expansion and cold shrinkage as well asstress generated during operation of the motor such that the supportingmember 13 and the positioning member 15 cannot be fixed in the axialtube 111, leading to unreliable positioning of the bearing 14. Namely,the bearing 14 is liable to move in the axial tube 111, shortening thelife of the motor 1. Improvement in the bearing positioning structurefor a motor is thus required.

OBJECTS OF THE INVENTION

An object of the present invention is to provide a bearing positioningstructure for a motor with improved assembling reliability.

Another object of the present invention is to provide a bearingpositioning structure for promoting the assembling reliability andprolonging the life of the motor.

A further object of the present invention is to provide a bearingpositioning structure for a motor with improved effect in preventingentrance of dusts into the motor, thereby prolonging the life of themotor.

SUMMARY OF THE INVENTION

In accordance with an aspect of the present invention, a bearingpositioning structure for a motor comprises an axial tube and apositioning member. The axial tube receives a bearing and includes acoupling section. The positioning member includes a pressing portion anda coupling portion. The coupling portion of the positioning member isengaged with the coupling section of the axial tube for securelymounting the positioning member to the axial tube, with the pressingportion of the positioning member pressing against the bearing toposition the bearing in the axial tube.

Preferably, the coupling portion is formed on a bottom of thepositioning member.

Preferably, the positioning member includes a top portion, and thepressing portion extends axially from an underside of the top portion.

Preferably, the coupling portion of the positioning member is a hook oran engaging groove.

Preferably, a restraining member is mounted in the axial tube forlimiting axial movement of a shaft of a rotor.

Preferably, the coupling section of the axial tube is a flange.

Preferably, the flange of the axial tube includes an inclined guidingface for guiding the coupling portion of the positioning member toengage with the flange of the axial tube.

Preferably, a protrusion extends from a top portion of the positioningmember and has an end edge close to an inner face of a rotor.

In accordance with another aspect of the present invention, a bearingpositioning structure for a motor comprises an axial tube, a stator, anda positioning member. A bearing is received in the axial tube. Thestator includes a first coupling section. The positioning memberincludes a pressing portion and a coupling portion. The first couplingsection of the stator is engaged with the coupling portion of thepositioning member for securely mounting the positioning member to anend of the axial tube, with the pressing portion of the positioningmember pressing against the bearing to position the bearing in the axialtube.

Preferably, the coupling portion is formed on a top portion of thepositioning member.

Preferably, the positioning member includes a top portion, and thepressing portion extends axially from an underside of the top portion.

Preferably, the coupling portion of the positioning member is a hook oran engaging groove.

Preferably, a restraining member is mounted in the axial tube forlimiting axial movement of a shaft of a rotor.

Preferably, a protrusion extends from a top portion of the positioningmember and has an end edge close to an inner face of a rotor.

Preferably, the stator further includes a second coupling section, andthe axial tube includes an engaging portion for engaging with the secondcoupling section of the stator, thereby securely mounting the stator tothe axial tube.

Preferably, the first coupling section is a hook.

Other objects, advantages and novel features of this invention willbecome more apparent from the following detailed description when takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a conventional bearing positioningstructure of a motor;

FIG. 2 is an exploded perspective view, party cutaway, of a firstembodiment of a bearing positioning structure in accordance with thepresent invention;

FIG. 3 is a sectional view of the first embodiment of the bearingpositioning structure in accordance with the present invention;

FIG. 4 is a sectional view similar to FIG. 3, illustrating a secondembodiment of the bearing positioning structure in accordance with thepresent invention;

FIG. 5 is an exploded perspective view, party cutaway, of a thirdembodiment of the bearing positioning structure in accordance with thepresent invention; and

FIG. 6 is sectional view of the third embodiment of the bearingpositioning structure in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 2 and 3, a first embodiment of a bearing positioningstructure in accordance with the present invention comprises a base 2, arestraining member 3, a bearing 4, a positioning member 5, and a rotor6. Mounted to the base 2 is an axial tube 21 and a stator 22, whereinthe axial tube 21 may be assembled to or integrally formed with the base2 for receiving motor elements including the restraining member 3, thebearing 4, and the positioning member 5. The stator 22 may be of radialwinding type or axial winding type. The restraining member 3 restrainsaxial movement of a shaft 61 of the rotor 6 relative to the axial tube21. The bearing 4 may be an oily bearing, a ball bearing, a fluiddynamic bearing, etc. The shaft 61 is rotatably extended through thebearing 4. The positioning member 5 is engaged with the axial tube 21for reliably positioning the bearing 4 in the axial tube 21.

Still referring to FIGS. 2 and 3, the axial tube 21 of the firstembodiment in accordance with the present invention includes a couplingsection 211 that extends radially and annularly on an end edge of theaxial tube 21. Preferably, the coupling section 211 is a flange andincludes an inclined guiding face (not labeled) for guiding thepositioning member 5 to a position securely engaged with the couplingsection 211.

Still referring to FIGS. 2 and 3, the restraining member 3 of the firstembodiment in accordance with the present invention includes a pluralityof protrusions 31, a plurality of slits 32, and a through-hole 33. Theprotrusions 31 extend radially inward form an inner circumference of therestraining member 3 for restraining axial movement of the shaft 61,with a slit 32 formed between a pair of protrusions 31 adjacent to eachother to providing the protrusions 31 with improved deforming capacity.The through-hole 33 is defined by the protrusions 31 and in a center ofthe restraining member 3, with the shaft 61 extending through thethrough-hole 33 of the restraining member 3.

Still referring to FIGS. 2 and 3, the positioning member 5 of the firstembodiment in accordance with the present invention is preferably a ringand includes a through-hole 50, a top portion 51, a pressing portion 52,and a coupling portion 53. The through-hole 50 is defined in a center ofthe positioning member 5, allowing the shaft 61 to extend therethrough.The pressing portion 52 extends axially from an underside of the topportion 51 for pressing against the bearing 4, thereby positioning thebearing 4 in the axial tube 21. The coupling portion 53 may be a hook oran engaging groove. In this example, the coupling portion 53 is a hookformed on a bottom of the positioning member 5 for engaging with thecoupling section 211 of the axial tube 21.

Still referring to FIGS. 2 and 3, in assembly of the motor of the firstembodiment in accordance with the present invention, the restrainingmember 3 is placed into the axial tube 21, with an abrasion-resistantmember “a” sandwiched between the restraining member 3 and the bottomend of the axial tube 21 for preventing damage to the base 2 due tofriction resulting from rotation of the shaft 61 of the rotor 6. Then,the bearing 4 is mounted into the axial tube 21, with an end face of thebearing 4 abutting against the top of the restraining member 3. Thepositioning member 5 is then mounted to the axial tube 21 by moving thecoupling portion 53 of the positioning member 5 along the inclinedguiding face of the coupling section 211. Hence, the positioning member5 is reliably coupled to the upper end of the axial tube 21, with thepressing portion 52 of the positioning member 5 pressing against theother end face of the bearing 4. Hence, the bearing 4 is reliably fixedin the axial tube 21. Preferably, at least one washer “b” is mountedbetween the other end face of the bearing 4 and the pressing portion 52.Preferably, the washer “b” is a resilient washer or abrasion-resistantwasher.

Still referring to FIGS. 2 and 3, the shaft 61 is extended through anaxial hole formed by the through-hole 50 of the positioning member 5,the through-hole (not labeled) of the washer “b”, and the through-holes40 and 33 of the bearing 4 and the restraining member 3. Since thediameter of the through-hole 33 of the restraining member 3 is slightlysmaller than the diameter of an end 611 of the shaft 61, a force isapplied to forcibly pass the end 611 of the shaft 61 through thethrough-hole 33 that expands due to deformation of the protrusions 31.After the end 611 of the shaft 61 passes through the through-hole 33 anda necked portion 612 reaches the through-hole 33, the protrusions 31return to their original position and engage with the necked portion612, thereby limiting axial movement of the shaft 61 relative to theaxial tube 21.

Still referring to FIGS. 2 and 3, the shaft 61 rotates in the axial holeformed by the restraining member 3, the bearing 4 and the positioningmember 5 when the rotor 6 turns. Since the pressing portion 52 of thepositioning member 5 presses against an end face of the bearing 4 andsince the coupling portion 53 of the positioning member 5 reliablyengages with the coupling section 211 of the axial tube 21, the bearing4 is reliably fixed in the axial tube 21 without the risk of loosening,thereby enhancing assembling reliability of the motor elements andprolonging the life of the motor.

FIG. 4 illustrates a second embodiment of the bearing positioningstructure for a motor in accordance with the present invention. Ascompared to the first embodiment, the positioning member 5 of the secondembodiment further includes a protrusion 54 that extends axially from anouter face of the top portion 51 of the positioning member 5.Preferably, an end edge of the protrusion 54 is close to an inner sideof the rotor 6. This avoids dusts or impurities from entering the gapbetween the shaft 61 and the bearing 4 due to air currents resultingfrom rotation of the rotor 6. Thus, non-smooth operation of the rotor 6and damage to the bearing 4 or other elements are avoided. The life ofthe motor is prolonged accordingly.

FIGS. 5 and 6 illustrate a third embodiment of the bearing positioningstructure for a motor in accordance with the present invention. Ascompared to the second embodiment, the stator 22 of the third embodimentincludes a first coupling section 221 on top of the stator 22 forengaging with the coupling portion 53 of the positioning member 5.Hence, the positioning member 5 is reliably mounted to the end of theaxial tube 21 through the stator 22. Preferably, the coupling portion 53is an engaging groove for engaging with the first coupling section 221.Preferably, the coupling portion 53 is annularly formed along acircumference of the top portion 51 of the positioning member 5.

Still referring to FIGS. 5 and 6, the stator 22 of the third embodimentis engaged with the axial tube 21 by providing a second coupling section222 on a bottom portion of the stator 22 for engaging with an engagingportion 212 of the axial tube 21. Hence, the stator 22 is reliably fixedto the axial tube 21. Preferably, the engaging portion 212 is formed onan outer circumference of the axial tube 21 and corresponding to thesecond coupling section 222. Preferably, the first and second couplingsections 221 and 222 are hooks.

Still referring to FIGS. 5 and 6, in assembly of the motor elements ofthe third embodiment, the restraining member 3, the bearing 4, and thepositioning member 5 are mounted into the axial tube 21 in sequence.Next, the first coupling section 221 and the second coupling section 222of the stator 22 are respectively engaged with the coupling portion 53of the positioning member 5 and the engaging portion 212 of the axialtube 21 such that the stator 22 is reliably fixed to the axial tube 21,with the pressing portion 52 tightly pressing against an end face of thebearing 4. The assembling reliably is enhanced and the life of the motoris prolonged through engagement between the stator 22 and thepositioning member 5 that allows the positioning member 5 to be reliablyfixed to an end of the axial tube 21.

As mentioned above, in the conventional bearing positioning structurehas the drawback of easy deformation in the axial tube 111 due to heatexpansion and cold shrinkage as well as stress generated duringoperation of the motor such that the supporting member 13 and thepositioning member 15 cannot be fixed in the axial tube 111, leading tounreliable positioning of the bearing 14. Namely, the bearing 14 isliable to move in the axial tube 111.

In the present invention, the above drawback is eliminated by providinga positioning member 5 including a pressing portion 52 and a couplingportion 53, wherein the coupling portion 53 engages with a couplingsection 211 on the axial tube 21 or a first coupling portion 221 on thestator 22 and wherein the pressing portion 52 presses against thebearing 4 to position the bearing 4 in the axial tube 21. Thepositioning member 5 may further include a protrusion 54 extendingupward from the top portion 51 to prevent dusts or impurities fromentering the gap between the shaft 61 and the bearing 4. The assemblingreliability is enhanced and the life of the motor is prolonged.

While the principles of this invention have been disclosed in connectionwith specific embodiments, it should be understood by those skilled inthe art that these descriptions are not intended to limit the scope ofthe invention, and that any modification and variation without departingthe spirit of the invention is intended to be covered by the scope ofthis invention defined only by the appended claims.

1. A bearing positioning structure for a motor, comprising: an axialtube for receiving at least one bearing, the axial tube including acoupling section; and a positioning member including a pressing portionand a coupling portion; wherein the coupling portion of the positioningmember is engaged with the coupling section of the axial tube forsecurely mounting the positioning member to the axial tube, with thepressing portion of the positioning member pressing against the bearingto position the bearing in the axial tube.
 2. The bearing positioningstructure for a motor as claimed in claim 1, wherein the couplingportion is formed on a bottom of the positioning member.
 3. The bearingpositioning structure for a motor as claimed in claim 1, wherein thepositioning member includes a top portion and wherein the pressingportion extends axially from an underside of the top portion.
 4. Thebearing positioning structure for a motor as claimed in claim 1, whereinthe coupling portion of the positioning member is a hook or an engaginggroove.
 5. The bearing positioning structure for a motor as claimed inclaim 1 further comprising a restraining member mounted in the axialtube for limiting axial movement of a shaft of a rotor.
 6. The bearingpositioning structure for a motor as claimed in claim 1, wherein thecoupling section of the axial tube is a flange.
 7. The bearingpositioning structure for a motor as claimed in claim 6, wherein theflange of the axial tube includes an inclined guiding face for guidingthe coupling portion of the positioning member to engage with the flangeof the axial tube.
 8. The bearing positioning structure for a motor asclaimed in claim 1 further comprising a protrusion extending from a topportion of the positioning member, with the protrusion having an endedge close to an inner face of a rotor.
 9. A bearing positioningstructure for a motor, comprising: an axial tube for receiving abearing; a stator including a first coupling section; and a positioningmember including a pressing portion and a coupling portion; wherein thefirst coupling section of the stator is engaged with the couplingportion of the positioning member for securely mounting the positioningmember to an end of the axial tube, with the pressing portion of thepositioning member pressing against the bearing to position the bearingin the axial tube.
 10. The bearing positioning structure for a motor asclaimed in claim 9, wherein the coupling portion is formed on a topportion of the positioning member.
 11. The bearing positioning structurefor a motor as claimed in claim 9, wherein the positioning memberincludes a top portion and wherein the pressing portion extends axiallyfrom an underside of the top portion.
 12. The bearing positioningstructure for a motor as claimed in claim 9, wherein the couplingportion of the positioning member is a hook or an engaging groove. 13.The bearing positioning structure for a motor as claimed in claim 9further comprising a restraining member mounted in the axial tube forlimiting axial movement of a shaft of a rotor.
 14. The bearingpositioning structure for a motor as claimed in claim 9 furthercomprising a protrusion extending from a top portion of the positioningmember, with the protrusion having an end edge close to an inner face ofa rotor.
 15. The bearing positioning structure for a motor as claimed inclaim 9, wherein the stator further includes a second coupling sectionand wherein the axial tube includes an engaging portion for engagingwith the second coupling section of the stator, thereby securelymounting the stator to the axial tube.
 16. The bearing positioningstructure for a motor as claimed in claim 9, wherein the first couplingsection is a hook.